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Sphinx Guideline version 1

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3.4 Decoding With <strong>Sphinx</strong><br />

As mentioned above, you need the following files for decoding:<br />

Trained models<br />

Dictionary<br />

Filler dictionary<br />

Language model/ FSG<br />

Test data<br />

To get a list of arguments in <strong>Sphinx</strong>3 decode, just type sphinx3_decode in the command line. You<br />

will get a list of arguments and their usage.<br />

In general, the configuration file needs, at the very least, to contain the following arguments:<br />

-hmm followed by the acoustic model directory<br />

-dict followed by the pronunciation dictionary file<br />

-fdict followed by filler dictionary<br />

-lm followed by the language model, OR<br />

-fsg followed by the grammar file<br />

-ctl followed by the control file (fileids)<br />

-mode fsg (for FSG, for n-gram let it be the default mode, so need to specify this for n-gram)<br />

However, in this case, there are several additional arguments that are necessary:<br />

-adcin yes (tells the recognizer that input is audio, not feature files)<br />

-adchdr 44 (tells the recognizer to skip the 44-byte RIFF header)<br />

-cepext .wav (tells the recognizer input files have the .wav extension)<br />

-cepdir wav (tells the recognizer input files are in the 'wav' directory)<br />

-hyp followed by the output transcription file<br />

In case your training arguments are different from default arguments, then set it manually by<br />

providing the following parameters.<br />

-hypseg \ (followed by Recognition result file, with word segmentations and scores)<br />

-logfn \ (followed by Log file (default stdout/stderr))<br />

-verbose yes \ (Show input filenames)<br />

-lowerf 133.33334 \ (Lower edge of filters)<br />

-upperf 3500 \ (upper edge of filters)<br />

-nfft 256 \ (Size of FFT)<br />

-wlen 0.0256 \ (Hamming window length)<br />

-nfilt 33 \ (Number of filter banks)<br />

-ncep 13 \ (Number of cep coefficients)<br />

-samprate 8000 \ (Sampling rate)<br />

-dither yes (Add 1/2-bit noise)<br />

The parameters like lowerf, upperf, nfft, wlen, nfilt,ncep should be same as used for training for<br />

good results.<br />

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